1. Field of the Invention
The present invention relates to a rotary cutter having a saw blade. More particularly, the present invention relates to a device for reducing vibrations of the saw blade during its rotation.
2. Description of the Related Art
Rotary cutters having saw blades such as circular saws, rotary chip saws, rotary diamond-blade saws or the like are generally known. In such rotary cutters, rotations of the saw blade cause vibrations of the blade body which in turn create noise.
The vibrations of the blade body during rotation can also cause accidental chips and/or burrs on the cut surface of a work, resulting in a poorly finished cut surface. Extended use of saw blades subject to vibration deteriorates the cutting edges at the periphery of the saw blades thereby reducing their product life. In addition, in order to improve working conditions, it is desirable to minimize vibration as well.
In order to solve the foregoing problems, the present inventor proposed a rotary cutter vibration damper in Japanese Laid-Open Utility Model Publication No. 2-31620. That vibration damper is shown generally in FIG. 5. As shown in FIG. 5, a rotary cutter 21 has a rotary saw blade 23 which is covered with a safety guard 25. The guard 25 has a vibration damper 22 composed of an idler roller 27, a bracket 24, a shaft 26 and a coil spring 28. The vibration damper 22 is attached to the guard 25 by way of an attachment cover 29.
The shaft 26 penetrates both guard 25 and attachment 29 which support the shaft 26 such that the shaft 26 is movable back and forth. The bracket 24 is fixed to the tip of the shaft 26. The bracket 24 supports the idler roller 27, which is in contact with the rotary saw blade 23 and rotates in accordance with the rotation of the saw blade 23. The coil spring 29 urges the shaft 26 in the direction that the idler roller 27 presses against the saw blade 23.
The idler roller 27 keeps in contact with the rotary saw blade 23 when the saw blade 23 is rotating, so that vibrations of the saw blade 23 are transmitted to the guard 25 by way of the vibration damper 22. This vibration energy is absorbed by the rotary cutter 21, and thus the vibration of the rotary saw blade 23 is reduced.